Reciprocating Compressor Temperature-Based Pressure Control

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Solution Overview

Problem

Reciprocating compressors face issues with performance degradation and wear when used outside their typical temperature range of 0°C to 40°C, leading to overheating, ring softening, and freezing, which can result in compressor failure, poor air discharge, and reduced lifespan.

Innovation Solution

A control method for reciprocating compressors that adjusts the start and stop pressures based on temperature readings from temperature sensors, reducing pressures when temperatures deviate from the normal range to prevent wear and maintain stability, including decreasing restart pressure at low temperatures and stop pressure at high temperatures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the compressor operates at high temperature outside the use temperature range, then the compressor can function in extreme environments, but overheating and ring softening occur leading to increased wear and potential failure

Engineering Contradiction:
Improvetemperature rangeVSAvoidcompressor stability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies parameter changes by adjusting the stop pressure threshold based on temperature conditions. When the temperature exceeds the predetermined range (indicating high-temperature operation), the control unit lowers the stop pressure threshold, causing the compressor to stop earlier before overheating and ring softening occur. This dynamic parameter adjustment prevents thermal damage while enabling operation in extreme temperature environments, thus resolving the contradiction between adaptability and reliability.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If the compressor operates at low temperature outside the use temperature range, then the compressor can function in cold environments, but freezing of drain and cylinder alumite wear occur leading to poor air discharge and reduced lifespan

Engineering Contradiction:
Improvetemperature rangeVSAvoidfreezing and wear
Core Design Contradiction:
Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary anti-action by implementing preventive measures before freezing and wear damage occurs. The control unit detects when temperature falls below the predetermined range and preemptively adjusts the start and stop pressure thresholds to reduce operational cycles and loading on the cylinder. This preliminary protection prevents freezing of the drain and minimizes alumite wear caused by hardening of the compression ring, enabling reliable cold-weather operation.

Inventive Principle:
Principle #9Preliminary anti-action

3Device complexity

If the start and stop pressure thresholds are fixed, then the control system is simple, but the compressor cannot adapt to temperature variations leading to performance degradation and increased wear

Engineering Contradiction:
Improvecontrol systemVSAvoidcompressor stability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent applies dynamics by transforming the fixed pressure thresholds into dynamic, temperature-dependent parameters. The control unit continuously monitors temperature and adjusts the start and stop pressure thresholds in real-time based on whether the temperature is within or outside the predetermined range. This dynamic adaptation allows the compressor to optimize its operation for current thermal conditions, preventing wear and performance degradation while maintaining a relatively simple control architecture.

Inventive Principle:
Principle #15Dynamics

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables stable operation of reciprocating compressors across a wider temperature range by reducing wear and preventing performance degradation, thus extending the compressor's lifespan and maintenance cycle.

Implementation Method 1

a temperature measured by at least one temperature sensor attached to the reciprocating compressor is outside a predetermined temperature range

Methodology Applied
Scientific EffectTemperature detection:

Data Source

PatentEP3553316B1Reciprocating compressor and control method therefor
Publication Date: 2023.06.21 HITACHI IND EQUIP SYST CO LTD
  • EP3553316B1 patent drawingFigure 1
  • EP3553316B1 patent drawingFigure 2~3
  • EP3553316B1 patent drawingFigure 4~5

AI summary

The purpose of the present invention is to provide a reciprocating compressor which is a compact, light-weight, portable air compressor such that deterioration of performance due to problems such as wear on the surface finish of the cylinder when the compressor is used for a long period of time outside the operating temperature range thereof is prevented. To achieve this, the cylinder temperature is detected, and control is carried out so that the compressor is restarted at a lower restart pressure when the temperature is lower than a prescribed value and stopped (and also restarted, preferably) at a low pressure when the temperature is higher than a prescribed value.